Results are reported for the f-electron intermetallic CeAuAl4Ge2, where the atomic arrangement of the cerium ions creates the conditions for geometric frustration. Despite this, magnetic susceptibility measurements reveal that the low temperature magnetic exchange interaction is weak, resulting in marginally frustrated behavior and ordering near TM≈ 1.4 K. This occurs within a metallic Kondo lattice, where electrical resistivity and heat capacity measurements show that the Kondo-driven electronic correlations are negligible. Quantum oscillations are detected in ac-magnetic susceptibility measurements and uncover small charge carrier effective masses. Electronic structure calculations reveal that when the experimentally observed antiferromagnetic exchange interaction and the on-f-site Coulomb repulsion (Hubbard) U are considered, the f-electron bands move away from the Fermi level, resulting in electronic behavior that is dominated by the s-, p-, and d- bands, which are all characterized by light electron masses. Thus, CeAuAl4Ge2 provides a starting point for investigating geometric magnetic frustration in a cerium lattice without strong Kondo hybridization, where calculations provide useful guidance.
@article{arxiv.1705.08271,
title = {Electronic Structure and Magnetism in the Layered Triangular Lattice Compound CeAuAl$_4$Ge$_2$},
author = {S. Zhang and N. Aryal and K. Huang and K. -W. Chen and Y. Lai and D. Graf and T. Besara and T. Siegrist and E. Manousakis and R. E. Baumbach},
journal= {arXiv preprint arXiv:1705.08271},
year = {2017}
}